JAAOS2018 Flashcards
Radiation dose relationship to proximity?
<div>radiation exposure DECREASES proportional to square of distance from source to surgeon (ie, small increases in distance = exponential decreases in radiation exposure)</div>
Types of radiation exposure effects?
Effects of Radiation<div><div>Exposure Deterministic</div><div>Effects Health consequences that occur after certain threshold of photons absorbed (eg, cataracts, hair loss, infertility)</div><div><br></br></div><div>Stochastic effects</div><div>Health consequences that occur randomly (each additional photon absorbed increases risk, but no threshold exists.) Mostly applied to health consequences as a result of DNA damage Eg, Cancer<br></br></div></div>
Most susceptible tissue to cancer induction from radiation? (higher number more sensitive)
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Yearly radiation dose limit?
<div>20mSv/ year (ICRP), or 50mSv/year (NCRP). ICRP is international, and is the lower limit, so safer to use this one</div>
<div>1 Sv of cumulative radiation exposure =</div>
1 Sv of cumulative radiation exposure =<div>60% increase in risk of developing solid cancer</div><div>5% increase absolute risk of mortality from cancer</div><div>so, if exposure limit set at 20mSv/year, 50 years required before one is exposed to 1Sv, and getting the above mentioned risks</div><div><br></br></div><div>Cataract risk = same threshold risk for 20mSv/year</div><div><br></br></div><div>Offspring risk</div><div>Highest risk during 1st trimester (organogenesis)</div><div><br></br></div><div>Stochastic effect of increased fetal cancer risk RR of 1.4 for every 10mGy …but absolute risk of childhood cancer after 10mGy = 0.3%, and baseline absolute risk = 0.2%</div><div><br></br></div><div>ICRP still recommends prenatal radiation exposure limit of 0.5mSv/mo during pregnancy<br></br></div>
Methods to decrease radiation exposure?
Lead apron 0.25-.5mm thick (blocks 90-95%)<div>Leaded glasses (reduces 90%) - eliminates risk of cataracts</div><div>C-position - stand on intensifier side (4-8x less)</div><div>- 1 m away (only get -.3% of dose)</div><div>- Other staff > 2m away<br></br><div><br></br></div></div>
Effects of Vit D on Skeletal Muscle?
- Enhanced myosin on actin -> more forceful contraction<div>2. Stronger UE/LE indices</div><div>3. Increased vertical ump</div><div>4. Lower incidence of stress fracture</div><div><br></br></div><div>JAAOS - Effects of Vitamin D on Skeletal Muscle and Athletic Performance</div><div><br></br></div>
Felix classification of periprostehtic tibial stress fractures?
“Based on location and I-IV and stability A/B, C = intrap<div><br></br></div><div><img></img><br></br></div>”
Indications for ALL reconstruction?
- young<div>- active</div><div>- pathologic rotatory laxity and imaging suggesting ALL injury</div><div>- Revision ACL wthout other factors causing failure</div>
Factors to optimize fracture healing?
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4 known muscle/bone factors implicated in supporting inflammatory phase of bone healing?
ILGF-1<div>Myostatin</div><div>BMPs (1)</div><div>Osteonectin</div>
Inflammatory cascade of # hematoma?
Migration of PMN (hours)<div>Macrophages replace neutrophils</div><div>T lymphoctytes initiate adaptive immune response</div><div>Mast cells help in bone repair<br></br></div>
RF for poor bone heaing in DM?
- peripheral neuropathy<div>- Operative time inc 15% risk for every 10 mins (past a set time..)</div><div>- HbA1C > 7</div>
Patient related risk factors for poor bone healing?
- DM 1 and 2<div>- NSAIDs</div><div>- Recent MVC</div>
RF for distal femur non-union
- obesity<div>- open</div><div>- infection</div><div>- stainless steel plate</div><div>(note - smoking, DM, steroids not on there)</div>
RF for revision surgery in tibial non-union?
- open<div>- transverse</div><div>- # gap</div><div>(No smoking/DM or steroids)</div>
Contraindication to VAC?
CSF leak<div>Bleeding disrder</div><div>Allergic to dressing</div>
Mechanism of VAC?
Speeds up 2nd intent<div>Increase blood flow</div><div>Removes edema and exudate</div>
RF for high risk SS complications (i.e. Consider a VAC)
DM, ASA >3, obesity smoker, hypoalbumin, steroids, high tension, revision
Contraindications to DFVO?
Absolute<div>Extreme valgus with tibial subluxation</div><div>Gross knee instability</div><div>Tricompartmental OA</div><div><br></br></div><div>Note: medial OA is absolute contra-indication, whereas moderate PF OA can be addressed with VDRO (although severe PF OA should be tx with arthroplasty) (medial OA)</div><div>Flexion contracture >15 deg</div><div><br></br></div><div>Relative Patient:</div><div>high BMI, RA, age>65 Knee: severe PF OA, severe lat comp bone loss, hx of SA<br></br></div>
Transfibular approach in TAA?JAAOS
Preserves deltoid ligament. Sacrificed ant talofibular… keeps skin blood supply, less bone loss
1st time dislocator OA?
> 50% develop some evidence of OA regardless of treatment.<div>ALso directly related to #d/l, cartilaginous trauma and timing or stabilization</div>
MPFL Origin and Insertion?
DA to Add tubercle (distal anterior)<div>Prox 1/2 of patella and quads tendon</div><div>Isometric</div>
Pathognomonic findings of patellar instability?
“Spur, double contour, crossing sign<div>Must have true lateral.</div><div><div> <div> <div><img></img></div> </div></div></div>”
Which half is it now?
Who scored last in this match?
What did you play last week?
Did your team win the last game?
